Ive oftened wondered as well had the history of Welsh football been different during those founding years/decades, with a trajectory more like Scotland/Ireland (that is completely Welsh, without offers or interest from the Southern League etc).

Appreciating Erics point about Cardiff at the turn of the century but I dont think multiple (say two) half decent teams (within the context of what standard that league would end up being) would be totally out of the question and then sustainable as the city grew.

I think the Welsh experience would be closer to both Irish leagues, rather than Scotland where I do think Erics onto something with the Glasgow experience (second city of the empire etc).

In Belfast there are a few teams at a similar level for example, ditto Dublin. So I guess just imagine in an alt universe Riverside FC staying as that and maybe one more club somewhere else in the city sprouting up to challenge perhaps (another one to ponder on - where?). Then most other places in Wales end up with one main representative team as is the case now.

Another alt history or counter factual for football in Wales is a similar one to this but where rugby hadnt existed / taken root in (south) Wales.